Method and apparatus for treating turf

ABSTRACT

A method and apparatus for treating turf to reduce the general soil density in which turfgrasses grow and thus promote turf growth and turf drainage which includes injecting through the turf into the soil a pattern of jets of generally incompressible liquid at a jet pressure and jet spacing to provide a lateral dispersion of the liquid within the soil such that the liquid dispersion from adjacent jets coact with one another to lift and fracture the soil. A plurality of small diameter nozzles are mounted on a movable frame generally transverse to the direction of travel of the frame. A pressurized fluid source is mounted on the frame and connected through a control device to the nozzles. The control device control the flow of liquid from the pressure source to the nozzles to produce periodic, relatively small cross-sectional, slugs, or jets, of liquid from the nozzles through the turf into the soil. The pressure on each slug of liquid is such that the liquid penetrates through the turf into the soil and also disperses generally laterally within the soil. The spacing of the nozzles and the speed of travel of the frame are such the lateral dispersion of each slug of liquid coacts with adjacent slugs to lift and fracture the soil, thereby reducing the compaction, or general density, of the soil and promoting turf growth and drainage.

BACKGROUND OF THE INVENTION

I. Field of the Invention

This invention pertains generally to a method and apparatus for treatingturf through turf and turf subsoil cultivation and more particularly toa method and apparatus which utilizes the discharge of properly spacedperiodic slugs, or jets, of pressurized incompressible liquid injectedinto the turf and turf subsoil to reduce soil compaction, or generaldensity, of the soil in which the turfgrasses grow.

II. Discussion of the Prior Art

Turfgrasses are utilized for functional, recreational and aestheticpurposes, including, but not limited to, the playing surfaces of turffacilities among them golf courses, parks, sports fields, cemeteries,highways rights of ways and industrial and home lawns. While thisspecification will discuss turf maintenance specifically with respect togolf course greens, it is to be understood that these maintenanceproblems exist with all turf facilities.

Intensive use of a turf area and maintenance operations often result inturf wear and soil compaction. This compaction reduces large, or macro,pore space and total pore space in the soil which in turn reduces waterinfiltration into the soil, percolation through the soil, and drainageout of the soil; limits exchange of soil gases, especially soil oxygen,with the atmosphere; and tends to restrict and reduce root growth anddevelopment of turfgrasses, for example, causing, in some cases,substantial reduction of the root system and often death of deeperroots.

The proper cultivation of turf to enhance drainage, and thereby thoroughroot growth, and improve the soil-air-water relationship has long been aproblem within the industry, and a great number of devices have beenproposed in the past in an effort to find a solution.

Core cultivation (aerification) is widely utilized as a long-termprogram to alleviate compacted conditions in the soil root zone. Severaldifferent types of core cultivation equipment are availablecommercially. One such type is the Toro Greensarator. Core cultivationequipment utilize vertically operating hollow or solid metal tines whichare forcibly driven into the turf to a depth of 21/2 to 3 inches extracta plug, or core, of the turf which is then deposited on the turf surfaceof the green. (In all instances the cores are collected and removed fromthe green and may be dried and used in a mix which is returned to thegreen to fill the holes).

Research has shown that core cultivation creates a serious problem.Repeatedly forcing the metal tines into the turf to a common depth will,over time, create a compacted subsurface layer of soil, sometimes calledplow sole, at a depth about one inch deeper than the length of thetines, in other words at about 31/2 to 4 inches below the surface of theturf. Further, the metal tines also tend to glaze the soil and createsome compaction along the sides of the coring hole. This subsurfacecompaction creates two major problems with proper turf management.First, the compacted layer interferes with proper water movement withinthe soil, and second, the compacted layer interferes with proper rootgrowth of the turf grasses. In addition to the compaction problem, corecultivation creates another problem--the removal or utilization of theremoved turf cores. Present techniques often leave a golf greenunplayable for two to three days after treatment. The present inventionprovides a method and apparatus which will allow immediate turf andsubsoil treatment at the time treatment is needed rather than waitingfor a convenient time, and thus allows immediate use of the treatedturf.

The present invention is a unique method and apparatus for accomplishingsubsoil cultivation which utilizes periodic turf and soil injection of asubstantially incompressible liquid, such as water, in a pattern, and atsufficient pressure, to lift and fracture the soil to reduce thecompaction, or general density, of the treated area. There are numerousprior art disclosures which use incompressible liquids for turftreatment, however, none of these references teach or suggest subsoilcultivation through the use of liquid injection to reduce soil density.

Marron et al, U.S. Pat. No. 2,930,334 discloses an apparatus forinjecting liquid compounds such as liquid fertilizers or weed killersinto the soil to be treated. Marron '334 gives no indication of any jetpressures, nor does Marron suggest liquid injection for the purpose ofreducing the general soil density. Indeed, Marron teaches the sequentialoperation of a series of liquid injection nozzles such that the patterngenerated could not create a significant reduction in soil density.

Baldwin et al, U.S. Pat. No. 3,012,526 discloses a method for injectingliquids into soil by imparting, through the application of highpressure, a high velocity to a slug of liquid to cause the unconfinedliquid slug to penetrate the soil. More particularly, Baldwin isdirected to a method of injecting liquids such as soil fumigants, liquidfertilizers, and insecticides by jet penetration. Nothing in the Baldwinteaches or suggests the pressures or injection spacing necessary tosignificantly reduce the general density of the treated soil.

Johnston, U.S. Pat. No. 2,988,025, and its U.S. Pat. No. Re. 25,307relate to methods of imparting highly volatile liquids, such asanhydrous ammonia, into soil for the purpose of fertilization orfumigation. Neither of the Johnston references teach or suggest theutilization of pressurized liquid injection to reduce compaction, or inother words, to reduce the general soil density so as to improvedrainage and turfgrass growth.

Johnston, U.S. Pat. No. 3,521,819 discloses a hydraulic device forintermittently ejecting slugs of liquid under pressure into the soil.Johnston '819 is specifically described as an improved apparatus forcarrying out the invention described in Baldwin, U.S. Pat. No. 3,012,526discussed above. Nowhere does the '819 patent, either alone or incombination with the Baldwin reference, suggest a method or apparatusfor reducing the general density of the soil in order to improve itsdrainage and thereby enhance root growth.

Collins, U.S. Pat. No. 3,926,131 and its continuation-in-part U.S. Pat.No. 4,034,686 disclose soil treating equipment which utilize liquidinjection tongs, or tines, which are mechanically driven into the soilto be treated. Each of the tongs have a nozzle adjacent its tip so thatliquid can be injected into the soil after the tong is buried in thesoil. Neither of the Collins references teach or suggest the injectionof slugs, or jets, of liquid at a pressure and spacing sufficient toreduce the general density of the treated soil.

Russell et al, U.S. Pat. No. 4,009,666 discloses an apparatus forinjecting liquids below the surface of the turf. The '666 patentdescribes the application of a continuous stream of liquid rather thanthe application of periodic slugs, or jets, of pressurized liquid.Nothing in the Russell patent teaches or suggests a method or apparatusfor reducing the general density of the treated soil.

Johnston, U.S. Pat. No. 4,624,193 is directed to a method and apparatusfor the jet injection of liquids into the soil. More particularly, the'193 reference pertains to the application of agricultural liquids toplants rather than the treatment of turf. Nothing in the Johnston '193patent teaches or suggests either the pressures or pattern spacingnecessary to accomplish a general reduction in soil density.

SUMMARY OF THE INVENTION

The present invention describes a method and apparatus for improvingturf grass management through turf and turf subsoil cultivation toreduce the general density of the treated soil in order to improve itsdrainage and the growth of grass roots.

The science of turf management and treatment is plagued with a myriad ofproblems. For example, all grasses do not respond the same to aparticular treatment. Indeed, the same grass may respond differentlydepending upon its location For example, the same grass, grown inWashington, Ill., and Florida may show widely different results whensubjected to the same treatment. Differences in soil, weatherconditions, and a host of other variables will have a significant impacton turfgrass treatment results. Extensive research has established thatthe subsoil cultivation that results from the present invention producessignificant improvement in turf growth over a wide range of varyingconditions.

The present invention provides a method for performing subsoilcultivation from a moving apparatus so as to reduce the general density,or compaction, of soil. The method includes a step of periodicallyinjecting, from above the turf to be treated, relatively smallcross-sectional spaced jets of generally incompressible liquid throughthe turf and into the soil. These jets, or slugs, of liquid are at apressure sufficient to cause a lateral dispersion of the liquid withinthe soil. In addition, the jet spacing is such that the lateraldispersion from adjacent jets coact with one another to lift andfracture the soil and reduce the general soil density.

While the subsoil cultivation of the present invention provideshydraulic aerification of the turf being treated, it goes beyond mereaerification of the turf and actually cultivates the subsoil by liftingand fracturing the subsurface soil to decrease its density. It is thisreduction in soil density that provides the great improvements inturfgrass growth and soil-air-water relationships.

The apparatus included within the present invention includes a frame anda suitable drive mechanism for propelling the frame at a given speedover the turf to be treated. A plurality of fluid nozzles are mounted onthe frame, the fluid nozzles being spaced a specified distance from eachother and in a direction generally transverse to the direction of travelof the frame. Each of the fluid nozzles has an input and output port.The output port of each nozzle is located a specified distance above theturf. A pump, or other suitable source of pressurized liquid, is alsomounted on, or in fluid engagement with, the frame along with a controldevice which periodically connects the source of pressurized liquid tothe input ports of each of the nozzles. The source of pressurizedliquid, in conjunction with the control device, periodically creates apressure at the nozzles sufficient to produce a jet, or slug, of fluidflow from the output port of each nozzle. These slugs of liquid are at apressure sufficient to cause the liquid to generally verticallypenetrate the soil and at the same time create a dispersion pattern ofthe liquid in a direction generally laterally from the direction ofpenetration. The distance between each nozzle, and the speed at whichthe frame is propelled over the turf, is controlled to provide acoaction between the dispersion patterns from each port so that thedispersion patterns of adjacent ports produces subsoil cultivation whichlifts and fractures the soil to reduce the general soil density.

It is an object of the present invention to provide a unique method andapparatus for treating turf by reducing the general density of the soilin which the turfgrasses grow in order to promote improved turf growthand improved drainage of the turf.

It is another object of the present invention to provide a unique methodand apparatus for treating turf which includes injecting, from above thesurface of the turf to be treated relatively small cross-sectionalspaced jets of generally incompressible liquid through the turf into thesoil.

It is still another object of the present invention to provide a uniquemethod and apparatus for treating turf by reducing the general densityof the soil in which the turfgrasses grow in order to promote improvedturf growth and improved turf drainage which includes injecting throughthe turf into the soil a pattern of relatively small cross-sectionaljets of a generally incompressible liquid at a jet pressure and at a jetspacing to provide a lateral dispersion of the liquid within the soilsuch that the liquid dispersion of adjacent jets coact with one anotherto lift and fracture the soil.

Another object of the present invention is to provide new and improvedapparatus for treating turf which includes a frame movable with respectto the turf to be treated and having a plurality of spaced, smalldiameter, nozzles mounted thereon in a direction generally transverse tothe direction of the frame, the nozzles being above, and spaced from,the turf to be treated. Also mounted on the frame is a source ofgenerally incompressible liquid which is connected through a controldevice to the spaced nozzles to produce periodic, relatively smallcross-sectional, slugs or jets of liquid from the nozzles through theturf into the soil at a pressure such that the liquid penetrates thesoil and also disperses generally laterally within the soil. The spacingof the nozzles and the speed of the frame are such that the lateraldispersion of each jet of liquid coacts with adjacent jets to lift andfracture the soil thereby reducing the compaction, or general density,of the soil to promote turf growth and drainage.

A further object of the present invention is to provide a method andapparatus for turf treatment which includes injecting jets of generallyincompressible liquid from above the surface of the turf to be treatedat a system pressure greater than or equal to 2300 psi.

These and other objects and advantages of the present invention willbecome apparent to those skilled in the art to which the inventionpertains from a consideration of the following detailed description of apreferred embodiment of the invention, especially when taken inconsideration of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing one embodiment of the subsoilcultivator of the present invention;

FIG. 2 is a rear elevation view of the cultivator shown in FIG. 1;

FIG. 3 is a left elevation view of the cultivator shown in FIG. 1;

FIG. 4 is a right side elevation view of the cultivator shown in FIG. 1,with the outline of the cultivator being shown in phantom and showingsome inner components thereof;

FIG. 5 is a bottom plan view of the cultivator shown in FIG. 1;

FIG. 6 is a right side elevation view of a tiller control section of thecultivator shown in FIG. 1;

FIG. 7 is a top plan view of the cultivator shown in FIG. 1 withportions thereof being shown in phantom, and showing some of the innercomponents;

FIG. 8 is an enlarged side elevation view of the rollers and nozzles ofthe cultivator shown in FIG. 1;

FIG. 9 is a perspective view of a portion of the water system of thecultivator shown in FIG. 1;

FIG. 10 is a schematic representation of the cultivator shown in FIG. 1

FIG. 11 is a sectional view of a side elevation of a metering valve andcam suitable for use in the present invention.

FIG. 12 is a sectional vertical plan view of the cam shown in FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, wherein like numerals represent like partsthroughout the several views, there is generally disclosed at 10 anapparatus for treating turf through subsoil cultivation so as to reducethe soil density. While the apparatus shown in the drawings is a walkbehind cultivator, it should be understood that the present inventionmay be practiced in a power driven rider version or in a trailer mountedversion suitable for towing by an independent drive mechanism.

The cultivator 10 includes a frame generally designated at 11. Thecultivator 10 has two modes of operation, a transport mode and acultivation mode. In order to permit movement of the cultivator 10during the transport mode of operation, the frame 11 is supported byfront wheels 12, and 13, and a steerable rear wheel 14 as shown in FIGS.1 and 2. The two front wheels 12 and 13 are connected to the frame 11 bymeans of a torsion axle 15 (FIG. 5). As shown in FIGS. 2, 3 and 4, thesteerable rear wheel 14 is connected to the frame 11 by means of asteering mount assembly 17. The steering mount assembly 17 has a domeshaped top which partially covers the top of the tire 14 and from whicha shaft 20 (FIG. 4) extends. One end of shaft 20 is rigidly connected tothe dome shaped top of the steering mount assembly while the other endof shaft 20 is rotatably mounted by means of a bearing 21. Bearing 21 ismounted in a plate 22 which in turn is rigidly connected to the frame11.

As will be described in more detail later, the cultivator 10 is drivenby means of an hydraulic motor 23 connected to an axle of the steeringwheel 14. Hydraulic motor 23 is supported by means of a bracket 24 (FIG.2) which is rigidly attached to the steering mount assembly 17.

One end of an elongated steering fork, or tiller, 25 is rigidlyconnected to the top of the steering mount assembly 17 by means of abracket 26. Preferably, the steering tiller 25 is hollow to accommodatecontrol wires and cables, to be more fully described hereafter.

A handle support bracket 27 is rigidly connected to the other end of thesteering tiller 25 by suitable means such as welding. As best shown inFIG. 6, the handle bracket 27 has a bottom edge 28 and a top edge 29.The top edge 29 of the handle bracket 27 has an elongated slot formedtherein in which is rigidly attached, as by welding, one side of arectangular handle 31 which may be made of any suitable material such astubing having a circular cross section. The other side of rectangularhandle 31 is cantilevered from the top edge 29 of handle bracket 27.

A parking brake handle 32 is pivotally mounted on the handle supportbracket 27 and is connected by a suitable linkage, such as cable 33, toa parking brake (not shown) operably connected to the powered steeringwheel 14. Braking may be accomplished by a downward (as viewed in FIG.5) movement of the parking brake handle 32.

A gas tank 34, having a fill cap 35, is positioned on frame 11, as shownin FIG. 1, and is connected thereto. Gasoline from gas tank 34 passesthrough a line (not shown) to a gasoline engine 36 (FIG. 7). The engine36, which may be of any suitable type such as an Onan 24 hp, is mountedby any suitable means (not shown) to the frame 11. A battery 37 andengine operating controls, located on a control panel 38, are alsomounted on frame 11 and connected to the engine 36 by any suitable meanswell known in the art.

As best shown in FIGS. 7 and 10, a first engine pulley 41 is connectedto an output shaft of the engine 36 and is connected by means of a belt42 to a pump pulley 43 which is mounted on a shaft of an hydrostaticpump 44. Pulleys 41 and 43 are constantly turning as long as engine 36is running. Oil from a gear box 45 is fed through an inlet tube 46 andacts as a source of oil for the pump 44. The hydrostatic pump 44 may beof any type well known in the art such as a Hawk HC600 pump from HotsyCorp. of Colorado Springs, Colo.; a Cat Model No. 3507 from Cat PumpsCorporation, P.O. Box 885, Minneapolis, Minn. 55440; or a Giant ModelNo. LP 501W from Giant Products, 3156 Bellevue Road, Toledo, Ohio 43606.

The direction and speed of operation of the hydrostatic pump 44, andhence the direction and speed of operation of the cultivator 10, iscontrolled through the operation of motor control 1 lever 47 (FIG. 1).Depending upon the direction which the motor control lever is moved fromthe vertical, the hydrostatic pump 44 will pump oil out of either anoutput line 50 or an output line 51 to the hydraulic drive motor 23connected to wheel 14, thereby driving the motor 23 either in forward orreverse. The speed at which the hydraulic drive motor 23 is driven isdetermined by how far the motor control lever is moved from the verticalin either a forward or backward movement. A throttle control bar 52 ispivotally mounted to the handle support bracket 27. Rotational movementof the throttle control bar forward moves the cable 53 in a firstdirection and rotational movement backward causes movement of the cable53 in an opposite second direction such linkage being well known in theart. The cable 53 is connected so as to cause hydrostatic pump 44 tooperate the hydraulic motor 23, and hence wheel 14, in a forward orreverse direction depending upon the direction of movement of thethrottle control bar 52.

Any suitable linkage between the throttle control bar and the motorcontrol lever and the hydrostatic pump 44 may be utilized to control thedirection and speed of hydraulic motor 23. One such linkage is describedin detail in a copending patent application of Dean A. Podevels et altitled METHOD AND APPARATUS FOR SOIL CULTIVATION BY HIGH PRESSURE FLUIDINJECTION and filed concurrently with the present application.

As indicated previously, the cultivator 10 has two modes of operation, atransport mode and a cultivation mode. When used in the cultivationmode, the front wheels 12 and 13 are raised and the cultivator 10 issupported by a roller assembly 54 best shown in FIGS. 8 and 9.

A detailed description of a mechanism for lifting the front wheels 12and 13 during the cultivation mode, as well as a detailed description ofthe roller assembly 54, is contained in the previously identifiedPodevels et al patent application and will not be repeated here.

Referring to FIGS. 4, 5, 7, 9, 10 and 11, a clutch 55 is connected tothe output shaft of the engine 36 and engages and disengages a secondengine pulley 56.

A water pump 57 having a low pressure inlet port 58 and a high pressureoutlet port 59 is mounted on frame 11 and a water pump pulley 60 on adrive shaft of the water pump 57 and is driven by means of a belt 61which engages both the water pump pulley 60 and the second engine pulley56.

A tube, or other suitable fluid conduit, 63 is connected between theoutput port 59 of pump 57 and an input port 64 of a metering valve 65.Metering valve 65 also has an output port 66 and a valve stem 67 whichopens or closes the fluid passage from the input to output ports 64 and66 of valve 65. A discharge tube 68 is connected to the output port 66of metering valve 65. The discharge tube 68 is preferably of metal andis of sufficient structural strength to support a nozzle bar 70. The bar70 may also be supported at other points along its length, if necessary.A plurality of nozzles 71 have input ports which are in fluidcommunication with the nozzle bar 70. As best shown in FIGS. 5 and 9,there are 11 nozzles 71 spaced apart along the nozzle bar 70 which inturn is mounted between the rollers of roller assembly 54. Each nozzle71 has an output port 72.

An accumulator 73, best shown in FIG. 10, has its input 74 in fluidengagement with the fluid conduit 63. Accumulator 73 has a charge, orfill, inlet 75 and a piston, or plunger, 76. The accumulator may beeither gas or spring operated, and may be of either the piston orbladder type. One suitable accumulator used in the present invention isa 4 inch I.D. nitrogen charged Accumulator A4J005C149J from ParkerHannifin Corp. of Hillsborgh, N.C. Another such accumulator is aGreer-Bladder Type Model #50A 1/4 WS, Part No. 842310 from GreerHydraulics, 6500 East Slauson Avenue, City of Commerce, Calif. 90040.

As shown in FIGS. 5 and 7, a right side hose fitting 77 is mounted inthe right side of frame 11 while a left side hose fitting 78 is mountedin the left side. Hoses 80 and 81 are connected at their first ends tothe hose fittings 77 and 78 respectively and at their second ends to a Tconnector 82. A water strainer 83 is connected between the output of theT connector 82 and the inlet port 58 of the water pump 57 by means of ahose 84.

FIG. 11 shows one embodiment utilized to meter and control the timing ofthe injections of high pressure liquid through the turf into the soil.The fluid conduit 63 was connected to the input port 64 of the meteringvalve 65 which in turn is in fluid engagement with the output port 66,i.e. the valve seat, of valve 65. The valve stem 67, shown in a splitrelationship indicating both the open and closed position, is normallyclosed preventing the fluid from fluid conduit 63 from entering a valvechamber 90 and exiting an output connection 91. As shown in FIG. 11, thevalve stem 67 is connected to a plunger 92 of a slide mechanism 93. Acompression spring 98 housed within mechanism 93 biases plunger 92 andstem 67 toward valve 65. Slide mechanism 93 is connected to the frame 11(connection not shown) so that it can move in a vertical direction only(as shown in FIG. 11). Slide mechanism 93 has a cam follower 94 whichrides in a cam 95, the track 96 of which is shown in vertical plan viewin FIG. 12. As shown, the cam track 96 has a cam follower actuator 97which moves the slide mechanism in a downward direction (as shown inFIG. 11) with each revolution of the cam 95. The downward movement ofthe slide mechanism 93 pulls the valve stem 67 away from the output port66 and allows the high pressure liquid from the fluid conduit 63 toenter the valve chamber 90 and exit out of the output connection 91 intothe discharge tube 68 and ultimately through the output ports 72 of thenozzles 71. While only one cam follower actuator 97 is shown in FIG. 11,is will be understood by those skilled in the art the several such camfollower actuators can be included in the cam track 96 to provide anydesired timing of the metering valve 65 at any rotational speedconsistent with value opening and closing times of from 0.007 to 0.065seconds. In a specific test of the present invention the system pressureutilized was 5000 psi, and the input port 64 of valve 65 had a diameterof 0.50 inches. In this application the pressure against the valve stem67 was approximately 1000 pounds. In this specific application a springpressure of approximately 1250 pounds was found to provide a sufficientholding pressure prior to activation of the valve opening by the cam.

Another accumulator and metering valve arrangement is disclosed in thecopending Podevels et al patent application previously described, and isincorporated by reference herein.

In operation, the engine 36 of the subsoil cultivator 10 is started fromcontrols which are located on the control panel 38 located on the rightside of frame 11 as shown in FIG. 1. These controls are described in thecopending Podevels et al application previously discussed and hence willnot be repeated here. It has been found that it is preferable to have astart and stop button on the support bracket 27 as well as the toggleswitch 30 for raising and lowering the rear wheels. By locating thecontrols in such a position, it is possible for an operator to operatethe apparatus 10 from one position. Operation of the present inventioncan be understood from a consideration schematic representation shown inFIG. 10. When the engine 36 is operating, the hydrostatic pump 44 isdriven by means of the pulleys 41 and 43 and belt 42. The pump 44 isalways driven as there is no clutch associated with the pump 44. If thepump 44 is stroked in a first direction, the oil will flow out of theoutput line 50 to the hydraulic drive motor 23, causing the steerabledrive wheel 14 to rotate and the cultivator 10 to go in a firstdirection. If the pump 44 is stroked in the other direction, oil willflow through output line 51 to the hydraulic motor 23 and the cultivator10 will be driven in the opposite direction.

Engine 36 drives the water pump 57 through the engine pulley 56, belt57, and pump pulley 60. Low pressure water is fed to the inlet port 58of the water pump 57 which then pumps the water through the fluidconduit 63 to the inlet port 64 of the metering valve 65. Since valve 65is normally closed through the operation of the valve stem 67, theoperation of pump 57 builds up a high pressure water in the fluidconduit 63. If nothing were done to control this pressure buildup thesystem would rupture or relief valves would be blown. The accumulator 73provides this control. The accumulator 73 shown in FIG. 10 is a gascharged type which has previously been charged with nitrogen, throughthe charge input 75, to a preset pressure. As the pump 57 builds uppressure in the closed fluid conduit 63 that exceeds the preset pressureof the accumulator, the pressurized water flows through the inlet port74 of accumulator 73 and engages the piston 74 which is free to movewithin the accumulator. Continued pumping of water into fluid conduit 63moves the accumulator piston against the nitrogen charge thus buildingup the pressure within the accumulator.

It should be understood that suitable pressure relief valves (not shown)may be incorporated in the fluid conduit 63 and the discharge tube 68 inorder to protect against undue buildup of system pressure due to valvemalfunction, clogging or other reasons.

It is an important aspect of the present invention that the accumulatorbe charged to a pressure sufficient to allow the accumulator to storethe water output capacity of the pump during the time that the meteringvalve 65 is closed. By water output capacity of the pump is meant thevolume of liquid pumped at pump pressure. In other words, theaccumulator should be charged such that it will store the volume ofliquid pumped during the time that the metering valve 65 is closed at anaccumulator pressure equal to the desired output pressure at the outputports 72 of the nozzles 71. It has been found that generally theaccumulator should be charged to about one half the nozzle outputpressure. Another purpose of the accumulator 73 is to smooth the flow ofliquid through the system when the metering valve 65 is open.

Engine 36 drives a cam 95 which acts on the valve stem 67 of meteringvalve 65 and periodically opens the valve. When valve 65 is open thepressurized liquid flows from the accumulator 73 through valve 65,discharge tube 68, nozzle bar 70, nozzles 71 and out the nozzle outputports 72. These slugs, or jets, of high pressure liquid are driven to asubstantial depth through the turf and into the soil. The high pressureof the liquid causes not only a penetration of the soil but also alateral dispersion of the liquid within the soil.

In accordance with the present invention the spacing of adjacent nozzles71 on the nozzle bar 70; the height of the nozzle outputs above thesurface of the turf; the speed movement of the cultivator 10 over theturf to be treated; and the timing of the periodic opening and closingof the metering valve 65; as well as the operating pressure of thesystem are correlated so as to create a pattern of liquid injectionssuch that the lateral dispersion of water from adjacent injections coactto lift and fracture the soil and thus reduce the soil's generaldensity.

It has been determined that, at a system pressure of approximately 5000psi, the distance of the output ports 72 of the nozzles 71 from thesurface of the turf can be varied from 0.50 to 5 inches with thepreferable spacing being between 0.50 and 1.50 inches. At the higherdistance, i.e. 3 to 5 inches, it has been found that the jets of waterwill entrain air and will carry this entrained air deep within the soil.However, it has also been found that injection of high pressure liquidfrom these higher elevations has a tendency to disrupt the surface ofthe turf. For this reason spacing of the output ports of the nozzles atthe higher elevation should not be utilized on surfaces, such as a golfcourse green, where the disruption may present problems, such as theprevention of immediate play after cultivation. When I refer todisruption of the turf with the nozzles at a higher elevation it shouldbe understood that I am comparing the disruption with the action of thecultivator when the nozzles are at a lower elevation and not with thedisruption created to the surface of the turf being treated by thehollow or solid tine core aerators. The surface disruption created bythe hollow and solid tine aerators is always more severe thanexperienced with the present invention.

It has also been determined that the accumulated area of the outputports 72 of the nozzles 71 has a direct relationship to the area of theoutput port 66 of the metering valve 65. It has been found that the areaof the outlet port 66 should be from 6-14 and preferably 8-10 times thetotal accumulated area of the output ports 72 of the nozzles 71. Itshould be understood that when referring to the output port of the valve65 I am referring to the cross-sectional area of the valve seat withinthe valve. In addition, it is necessary that the input port 64 as wellas the associated system tubing be consistent with this relationship,i.e. the cross sectional areas of these systems components must be equalto, and preferably larger, than the cross-sectional area of the outputport 66

I have further determined that the injection pressure from the outputports 72 of the nozzles 71 should be equal to, and preferably greaterthan, 2300 psi with a pressure of approximately 5000 psi beingpreferred.

In one test application of the present invention a system pressure of5000 psi was utilized. From nine to thirteen nozzles 71 were utilized onthe nozzle bar 70 and the diameter of the output ports 72 of the nozzleswas 0.0465 inches. The diameter of the output port 66 of the meteringvalve 65 was 0.50 inches. The charge of the accumulator 73 was 2500 psi,and the capacity of the accumulator was approximately one quart. Thecycling speed of the metering valve, i.e., the opening to closing time,was from 0.015 to 0.065 seconds. The diameter of the output ports 72 ofeach of the nozzles 71 was 0.0465 inches. System tubing and connectionswere consistent with proper liquid injection as explained above. Thetest machine had a variable speed range from 0 to 31/2 miles per hour.The cam speed was set to provide three injections per second. The nozzlebar was replaceable with transverse nozzle spacing of 3 inches, 4inches, 5 inches or any multiples thereof. This nozzle bar arrangementpermitted tests to be conducted with transverse liquid injections spaced3, 4, 5, 6, 8, 9, 10, etc. inches apart, with a forward spacing ofinjection varying from 0 to approximately 21 inches. Our tests indicatethat the most promising reduction in soil density occurs with anapproximate 2 to 6 inch square or rectangular injection pattern with the5000 psi system pressure. This spacing pattern is not absolute. It mustbe understood that the most important point is to maintain a jetinjection pattern which, consistent with the system pressure, willprovide a lateral dispersion of the incompressible liquid so as tosufficiently fracture the soil.

In severely compacted areas, the subsurface cultivator of the presentinvention can achieve very deep turf penetration through the repeatedapplication of slugs of liquid into the same hole in order to improvethe drainage. Turf penetration of thirty inches or more have beenobtained using the present invention. Deep penetration of highlycompacted turf can also be obtained by using fewer nozzles with largerdiameter output ports consistent with the system operating pressure andflow.

While I specifically described the use of water in practicing myinvention, it will be understood by those skilled in the art that anysubstantially incompressible liquid, such as incompressible liquidfertilizers or weed killers, may be used. The important factor is thatthe liquid have sufficient incompressibility so that the injectionpressure and jet spacing provides the turf penetration and lateraldispersion necessary to accomplish the lifting and fracturing of thesoil to significantly reduce the general soil density.

Further, while I describe a single row of generally transversely spacednozzles, it will be understood by those skilled in the art that multiplerows of transversely spaced nozzles may also be employed. By controllingthe timing of slug injection with the speed of the frame movement overthe turf to be treated, predetermined sections of turf may be treatedduring any specific injection sequence.

Finally, while in the embodiment shown the pressurized source ofincompressible liquid is carried on the frame, it should be understoodthat an external source of high pressure liquid may be utilized to feedfluid conduit 63 thus eliminating the need to carry water pump on theframe.

Other modifications of my invention will be apparent to those skilled inthe art in light of the foregoing description. This description isintended to provide specific examples of individual embodiments whichclearly disclose the present invention. Accordingly, the invention isnot limited to these embodiments or the use of elements having specificconfigurations and shapes as presented herein. All alternativemodifications and variations of the present invention which follow inthe spirit and broad scope of the appended claims are included.

I claim:
 1. A turf treating machine comprising:(a) a frame; (b) meansconnected to said frame for propelling said frame over the turf to betreated; (c) a plurality of fluid nozzles mounted on said frame, each ofsaid fluid nozzles being a specified distance apart from adjacentnozzles and having an input port and an output port, the output port ofeach nozzle being a specified distance above said turf; (d) pressurizedfluid generating means mounted on said frame; (e) control meansconnecting said pressurized fluid generating means to the input ports ofeach of said nozzles so as to produce periodic fluid injections from theoutput port of each said nozzle at a system pressure sufficient,commensurate with the spacing of said nozzles, to cause said fluid topenetrate through said turf into the soil in a first direction and atthe same time create a dispersion of said fluid in a direction generallyoutward from said first direction of penetration sufficient to coactwith dispersion patterns from adjacent nozzles to lift and fracture thesoil so as to reduce the general turf and turf subsoil density.
 2. Aturf treating machine as described in claim 1 wherein the systempressure is equal to or greater than 2300 pounds per square inch.
 3. Aturf treating machine as described in claim 1 wherein the output portsof the nozzles are spaced from 0.50 to 5.0 inches above the turf to betreated.
 4. A turf treating machine as described in claim 1 wherein theoutput ports of the nozzles are spaced from 0.50 to 1.5 inches above theturf to be treated.
 5. A turf treating as described in claim 1 whereinsaid control means includes means to provide for multiple injections offluid from the nozzles in the same spot to provide deep soilpenetration.
 6. A turf treating machine as described in claim 5 whereinthe system pressure is equal to or greater than 2300 pounds per squareinch.
 7. A turf treating machine as described in claim 1 wherein thepressurized fluid generating means is pressurized to approximately 5000pounds per square inch and the diameter of the output port of eachnozzle is 0.0465 inches.
 8. A turf treating machine as described inclaim 1 wherein the nozzles are spaced apart from one another in a rangeof from 2 to 8 inches.
 9. A turf treating machine comprising:(a) aframe; (b) means connected to said frame for propelling said frame in afirst direction over the turf to be treated; (c) a plurality of fluidnozzles mounted on said frame a specified spaced distance from eachother and in a direction generally transverse to said first direction,each of said fluid nozzles having an input and output port, the outputport of each nozzle being a specified distance above said turf; (d)pressurized fluid generating means mounted on said frame; (e) controlmeans periodically connecting said pressurized fluid generating means tothe input ports of each of said nozzles at a system pressure sufficientto produce a fluid flow from the output port of each said nozzle at anoutput pressure sufficient, commensurate with the spacing of saidnozzles, to cause said fluid to generally vertically penetrate throughsaid turf into the soil and at the same time create a dispersion of saidfluid in a direction generally lateral to said generally verticalpenetration sufficient to coact with dispersion patterns from adjacentnozzles to lift and fracture the soil so as to reduce the general turfand turf subsoil density.
 10. A turf treating machine as described inclaim 9 wherein the output ports of the nozzles are spaced from 0.50 to5.0 inches above the turf to be treated.
 11. A turf treating machine asdescribed in claim 9 wherein the output ports of the nozzles are spacedfrom 0.50 to 1.5 inches above the turf to be treated.
 12. A turftreating machine as described in claim 9 wherein the system pressure isequal to or greater than 2300 pounds per square inch.
 13. A turftreating machine comprising:(a) a frame; (b) means connected to saidframe for propelling said frame at a given speed in a first directionover the turf to be treated; (c) a plurality of fluid nozzles mounted onsaid frame a specified spaced distance from each other and in adirection generally transverse to said first direction, each of saidfluid nozzles having an input and output port, the output port of eachnozzle being a specified distance above said turf; (d) pressurized fluidgenerating means mounted on said frame; (e) control means periodicallyconnecting said pressurized fluid generating means to the input ports ofeach of said nozzles at a system pressure sufficient to produce a fluidflow from the output port of each said nozzle at an output pressuresufficient, commensurate with the spacing of said nozzles, to cause saidfluid to generally vertically penetrate through said turf into the soiland at the same time create a dispersion pattern of said fluid in adirection generally lateral to said generally vertical penetration, thespecified spaced distance between each output port and the speed atwhich the frame is propelled over the turf, in conjunction with theoutput pressure of said nozzles, being such that the dispersion patternsfrom adjacent output ports coact with one another so as to lift andfracture the soil so as to reduce the general turf and turf subsoildensity.
 14. A turf treating machine as described in claim 13 whereinthe output ports of the nozzles are spaced from 0.50 to 5.0 inches abovethe turf to be treated.
 15. A turf treating machine as described inclaim 13 wherein the output ports of the nozzles are spaced from 0.50 to1.5 inches above the turf to be treated.
 16. A turf treating machine asdescribed in claim 13 wherein the system pressure is equal to or greaterthan 2300 pounds per square inch.
 17. A turf treating machinecomprising:(a) a frame; (b) a drive mechanism connected to said framefor moving said frame in a given direction, and at a controlled speed,over the turf to be treated; (c) a plurality of fluid nozzlesoperatively connected to said frame a specified distance apart fromadjacent nozzles, each of said nozzles having an input and an output;(d) a pressurized source of generally incompressible liquid operativelyconnected to said frame, said pressurized source having an output; (e) avalve having an input and an output; (f) a fluid conduit mechanismconnected between the output of said pressurized source of generallyincompressible liquid and the input of said valve; (g) a fluid conduitconnected between the output of said valve and the inputs of each ofsaid plurality of fluid nozzles; (h) control mechanism for controllingthe operation of said valve and the movement of said frame over the turfto be treated such that the valve periodically releases high pressurejets of generally incompressible liquid from the output of the nozzlesat an output pressure commensurate with the speed of the frame over theturf and the spacing of said nozzles so that said jets of liquidpenetrate through the turf into the soil such that the dispersionpattern from the output of each nozzle in the soil generally coacts withthe dispersion pattern of adjacent nozzles so as to lift and fracturethe soil and reduce the general turf and turf subsoil density.
 18. Aturf treating machine as described in claim 17 wherein the area of theoutput of the valve is 6 to 14 times the accumulated area of the outputof the nozzles.
 19. A turf treating machine comprising:(a) a frame; (b)a drive mechanism connected to said frame for moving said frame in agiven direction, and at a controlled speed, over the turf to be treated;(c) a plurality of fluid nozzles operatively connected to said frame aspecified distance apart from adjacent nozzles, each of said nozzleshaving an input and an output; (d) a pressurized source of generallyincompressible liquid operatively connected to said frame, saidpressurized source having an output; (e) a valve having an input and anoutput; (f) a first fluid conduit connected between the output of saidpressurized source of generally incompressible liquid and the input ofsaid valve. (g) a second fluid conduit connected between the output ofsaid valve and the inputs of each of said plurality of fluid nozzles;(h) control mechanism for controlling the operation of said valve andthe movement of said frame over the turf to be treated such that thevalve periodically opens to release high pressure jets of generallyincompressible liquid from the output of the nozzles at an outputpressure commensurate with the speed of the frame over the turf and thespacing of said nozzles so that said jets of liquid penetrate throughthe turf into the soil such that the dispersion pattern from the outputof each nozzle in the soil generally coacts with the dispersion patternof adjacent nozzles so as to lift and fracture the soil and reduce thegeneral turf and turf subsoil density; and (i) an accumulator connectedto said first fluid conduit to store the output capacity of saidpressurized source between periodic openings of said valve.
 20. A turftreating machine as described in claim 19 wherein the system pressure isapproximately 5000 psi and the accumulator is charged to approximately2500 psi.
 21. A turf treating machine as described in claim 19 whereinthe accumulator is charged such that it will store the volume of liquidpumped during the time that said valve is not open at an accumulatorpressure equal to the desired system pressure.
 22. A turf treatingmachine comprising:(a) a frame; (b) a drive mechanism connected to saidframe for moving said frame in a given direction, and at a controlledspeed of from 0 to 3.5 miles per hour, over the turf to be treated; (c)a plurality of fluid nozzles operatively connected to said frame aspecified distance apart from adjacent nozzles, each of said nozzleshaving an input port and an output port; (d) an approximately 5000 psipressurized source of generally incompressible liquid operativelyconnected to said frame, said pressurized source having an output; (e) avalve having an input and an output, the output of said valve having anarea of from 6 to 14 times the accumulated area of the output ports ofsaid plurality of fluid nozzles; (f) a first fluid conduit connectedbetween the output of said pressurized source of generallyincompressible liquid and the input of said valve; (g) a second fluidconduit connected between the output of said valve and the inputs ofeach of said plurality of fluid nozzles, said first fluid conduit, saidsecond fluid conduit, and the input of said valve, each having crosssectional areas substantially equal to, or greater than, the crosssectional area of the output of said valve; (h) control mechanism forcontrolling the operation of said valve and the movement of said frameover the turf to be treated such that the valve periodically opens torelease jets of generally incompressible liquid from the output of thenozzles at an output pressure greater than 2300 psi, and at a speed ofthe frame over the turf and at a spacing of said nozzles so as toproduce a 2 to 8 inch rectangular injection pattern such that said jetsof liquid penetrate through the turf into the soil so as to lift andfracture the soil and the reduce the general turf and turf subsoildensity; and (i) an accumulator connected to said first fluid conduit tostore the output capacity of said pump between periodic openings of saidvalve.
 23. A turf treating machine comprising:(a) a frame; (b) a drivemechanism connected to said frame for moving said frame in a givendirection, and at a controlled speed of from 0 to 3.5 miles per hour,over the turf to be treated; (c) a plurality of fluid nozzlesoperatively connected to said frame in a range of from 2 to 8 inchesapart from adjacent nozzles, each of said nozzles having an input portand an output port; (d) an approximately 5000 psi pressurized source ofgenerally incompressible liquid operatively connected to said frame,said pressurized source having an output; (e) a valve having an inputand an output, the output of said valve having an area of from 6 to 14times the accumulated area of the output ports of said plurality offluid nozzles; (f) a first fluid conduit connected between the output ofsaid pressurized source of generally incompressible liquid and the inputof said valve; (g) a second fluid conduit connected between the outputof said valve and the inputs of each of said plurality of fluid nozzles,said first fluid conduit, said second fluid conduit, and the input ofsaid valve, each having cross sectional areas substantially equal to, orgreater than, the cross sectional area of the output of said valve; (h)control mechanism for controlling the operation of said valve and themovement of said frame over the turf to be treated such that the valveperiodically opens to release jets of generally incompressible liquidfrom the output of the nozzles at an output pressure greater than 2300psi, and at a speed of the frame over the turf and at a spacing of saidnozzles so as to produce a 2 to 8 inch rectangular injection pattern;and (i) an accumulator connected to said first fluid conduit to storethe output capacity of said pump between periodic openings of saidvalve.
 24. A turf treating machine as described in claim 23 wherein thesystem pressure is equal to or greater than 2300 pounds per square inch.25. A turf treating machine as described in claim 23 wherein the outputports of the nozzles are spaced from 0.50 to 5.0 inches above the turfto be treated.